1. Field of the Invention
This invention relates to plated anvils for surgical fastener applicators, and more particularly to PTFE available under the trademark TEFLON electroless nickel plating of the anvils.
2. Background of the Related Art
Surgical fastener applicators, such as staplers, have been utilized to join body tissue during invasive surgical procedures for some time. For example, in some surgical operations it is necessary to adjoin two hollow body organs alongside each other, generally with their longitudinal axes parallel to each other, and to effect a longitudinal cut through the contacting circumferential walls of the two organs so that the two organs constitute a single hollow chamber along the length of the cut. Correspondingly, the circumferential portions of the two adjoining organs on each lateral side of the cut must be sutured or otherwise attached by at least one line of "stitches" in order to maintain the integrity of the union.
Surgical fastener applicators utilized during the above described procedure provide handle assemblies which allow the surgeon to grasp the instrument in close proximity to the tissue to be adjoined and easily cause actuation of the stapling mechanisms. As a result, the forces required to form the staples have not been a primary design criteria when developing staplers for use in invasive surgical procedures.
On the other hand, endoscopic and laparoscopic procedures have recently advanced to the point where surgeons are performing increasingly complex and innovative surgical procedures using a wide variety of instruments including surgical fastener applicators. For background, in laparoscopic procedures, surgery is performed in the interior of the abdomen through a small incision, whereas in endoscopic procedures, surgery is performed in any hollow viscus of the body, e.g., through narrow endoscopic tubes inserted through small entrance wounds in the skin. Laparoscopic and endoscopic procedures generally require that any instrumentation inserted into the body be sealed, i.e., provisions must be made to ensure that gases do not enter or exit the body through the laparoscopic or endoscopic incision as, for example, in surgical procedures in which the surgical region is insufflated. Moreover, laparoscopic and endoscopic procedures often require the surgeon to act on organs, tissues, and vessels far removed from the incision, thereby requiring that any instruments to be used in such procedures be both long and narrow.
An example of a surgical fastener applicator adapted for such endoscopic and laparoscopic procedures is shown in commonly assigned U.S. Pat. No. 5,040,715 to Green et al. The applicator includes a handle assembly and a tubular portion having a jaw assembly positioned at its distal end. In one embodiment, the jaw assembly includes an anvil portion as one jaw and a fastener cartridge assembly as the other jaw. Generally, the fastener cartridge assembly has two, triple staggered rows of fasteners, such as staples, and a pusher bar/knife assembly between the two triple staggered rows. Since the general construction of the above described endoscopic applicator results in jaw assemblies which are removed from the handle assembly by a significant distance, the force required to form the staples has become a factor to be considered when designing these instruments.
As will be discussed in further detail below, copending Application Ser. No. 07/593,654, filed Oct. 5, 1990, discloses anvils plated with a metallic alloy which moderately reduced the force required to form the staples. However, further reduction of the requisite force necessary to form the staples is desirable.